/*
 * Copyright (C) 2009 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;

import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import javax.annotation.CheckForNull;

/**
 * List returned by {@link ImmutableCollection#asList} that delegates {@code contains} checks to the
 * backing collection.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 */
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial")
@ElementTypesAreNonnullByDefault
abstract class ImmutableAsList<E> extends ImmutableList<E>
{
    abstract ImmutableCollection<E> delegateCollection();

    @Override
    public boolean contains(@CheckForNull Object target)
    {
        // The collection's contains() is at least as fast as ImmutableList's
        // and is often faster.
        return delegateCollection().contains(target);
    }

    @Override
    public int size()
    {
        return delegateCollection().size();
    }

    @Override
    public boolean isEmpty()
    {
        return delegateCollection().isEmpty();
    }

    @Override
    boolean isPartialView()
    {
        return delegateCollection().isPartialView();
    }

    /**
     * Serialized form that leads to the same performance as the original list.
     */
    @GwtIncompatible // serialization
    static class SerializedForm implements Serializable
    {
        final ImmutableCollection<?> collection;

        SerializedForm(ImmutableCollection<?> collection)
        {
            this.collection = collection;
        }

        Object readResolve()
        {
            return collection.asList();
        }

        private static final long serialVersionUID = 0;
    }

    @GwtIncompatible // serialization
    private void readObject(ObjectInputStream stream) throws InvalidObjectException
    {
        throw new InvalidObjectException("Use SerializedForm");
    }

    @GwtIncompatible // serialization
    @Override
    Object writeReplace()
    {
        return new SerializedForm(delegateCollection());
    }
}
